1. Field of the Invention
This invention relates to an electric sleep inducer and more particularly to an electric sleep inducer arranged to apply an electric current to the head at low frequency values controlled to gradually decrease.
2. Description of the Prior Art
A. History of Electric Sleeping Devices:
It was Gilyarovskii, et al. of the U.S.S.R. who developed an electric sleeping device for the first time. This development stemmed from two ideas. The first one was a novel basic concept of Pavlov concerning sleep. Pavlov was successful in objectively grasping the process of stimulation and inhibition that broadly takes place in the cerebral cortex through his studies of conditional reflex. From this point of view, he was against a then prevalent theory that sleep was brought about by the stimulation of a sleep center and he established a new theory that a sleep represents essentially broadly inhibited state of the cerebral cortex.
The second indea involved electric convulsive therapy and electro-anesthetic therapy which began to be practiced during 1940 or thereabout, in the U.S.A. and England. These electrical therapies were applied to the treatment of mental disorder and were carried out in the following manner: First, a strong electric current of 150 to 250 mA was applied through electrodes positioned on both sides of the head. After that, the current lowered to 60 to 70 mA. Then, the current is either continuously applied at the lowered value or further lowered gradually.
As for a loss of consciousness which was one of the vital phenomena that was caused by the electrical therapy, this can be explained by introducing Pavlov's theory of the inhibited state of the whole cerebral cortex. Therefore, it may be considered that electric sleep therapy in its infancy was derived from the electric convulsive therapy and the electro-anesthetic therapy. It is therefore understandable that Gilyarovskii, et al. stated that the problem to be first solved in establishing electric sleep therapy was how to determine the positions of electrodes for obtaining the strongest effect of a current on the brain.
According to Gilyaroviskii, et al, a fundamental prerequisite to a successful electric sleep therapy is to have a wide inhibition of the cerebral cortex, i.e. to have no disagreeable sensation which prevents sleep from taking place; and on the other hand, it is desirable to apply as large an electric current as possible to a testee so long as the testee complains of no disagreeable feeling.
To satisfy these conditions, Gilyaroviskii, et al stated that, the electric sleeping device must have an electric power of 10 to 12 mA and at least 6 to 8 mA. Accordingly, what is most important is a complaint of the testee about a stimulant sensation. Therefore, while a condition of an electric stimulation suitable for bringing about inhibition over brain cells is considered to be at a frequency value between 1 to 20 Hz, an actual setting of frequency is 100 Hz in many cases.
B. Conventional Electric Sleeping Devices:
The electric sleeping device in its infant stage was arranged to have electrodes thereof applied to the eyes. In view of the structure of the skull, the orbits and the base of the skull, i.e. the eyes and the occiput, were considered most suitable for introducing an electric current into the cerebrum. Further, since a direct current mostly passes on the surface of the endocranium because of resistance of the endocranium, an impulse current has been used because it passes through the endocranium.
However, although positioning the electrodes at the orbit and the occiput certainly most suitably enables the introduction of current into the cerebrum, this arrangement tends to induce a photopsia, because it tends to affect the optic nerve which is very sensitive.
In short, the conventional electric sleep device has been developed by accepting in its entirety the concept of Pavlov that a satisfactory effect can be obtained from an efficient inhibition over the whole area of the cerebral cortex. At the initial stage of the therapy, an impulse of a relatively high frequency of 12 to 16 Hz is applied and then the frequency is gradually lowered to 1-2 Hz according as the working time elapses.
The above stated frequency is lowered in a stepwise manner as shown in FIG. 1 of the accompanying drawings. The stepwise decrease is carried out by manually turning a frequency change-over adjustment dial. The tester verbally inquires of the testee about the electric current stimulation at every step of frequency change-over. This takes much time and labor. Also, in accordance with this stepwise frequency lowering method, the instant at which the frequency is changed presents a problem, because: a difference that thus arises in the stimulation affects the living body to a considerable extent although it is merely a momentary effect. In this regard, a problem into arises since, one of the electrodes is placed on the eye. It has been reported, that there are some moments at which a light is felt with the optic nerve stimulated by the above stated effect which strongly appears at the time of opening and closing of the circuit.
C. The shortcomings of the Conventional Electric Sleep Device:
(1) The conventional electric sleep device requires much time and labor to operate. In determining an optimum galvanic stimulation, the tester depends on complaints from the testee.
(2) The device give excessive stimulation. The stepwise frequency lowering method causes the lowering degree of stimulation to strongly affect a living body, though the change of stimulation is over in a moment.
(3) The device is apt to stimulate the optic nerve. Since one of the electrodes is placed on the eye, the optic nerve which is sensitive is apt to be stimulated in an awakening manner.
(4) The shape of electrodes is complex and thus requires much time in attaching and removing them. One of the electrodes is arranged in a spectacle shape for the orbit while the other is arranged for the occiput. To inhibit the whole area of the cerebral cortex and also for close contact with the head skin, the electrode is provided with many small protrusions. The electrode of this type causes the water content with which it is imbued to quickly dry up. This requires extra care. Besides, the occiput must thoroughly be degreased with alcohol or the like before the electrode is attached to the occiput.
(5) Side effects frequently take place. Since it is a basic concept that a better effect can be obtained by applying the largest allowable electric current within the range of current values that do not cause the testee to complain of a disagreeable feeling under the electrical stimulation given to his head, a strong stimulation tends to be eventually given to the head. Then, this results in a case of photopsia, a skin scald, dizziness and a complication thereof.
(6) The range of adaptive syndrome is apt to be excessively broadened. In other words, as a result of a broadened interpretation of Pavlov's concept, internal diseases, surgical diseases, diseases of the central and peripheral nerve systems, skin diseases, etc. are included in the range of adaptive syndrome. Then, such an excess brings an insomnia treatment out of focus.
The present invention is directed to the obviation of such shortcomings of conventional devices with a novel electric head treating device developed according to a concept which differs from the conventional electric sleep device and is based on findings obtained from the literature on head galvanization and the results of recent great advances in the research of sleep.